Soil geomorphology on bedrock and colluvial terrain with permafrost in central Alaska, USA

Abstract

The depth to permafrost, thickness of the surface organic layer, and strength of redoximorphic features are closely correlated in soils on low-relief bedrock hills and colluvial slopes near Hughes, Alaska. Soils can be arrayed along a morphological gradient from warm-dry-mineral to cold-wet-organic, and the ranks of soils along this gradient correlate with topographic parameters and mineral soil texture. The warm-dry-mineral soils tend to occur on coarse-textured materials, convex slopes, steep slopes, and south-facing slope aspects, while the cold-wet-organic soils tend to occur on fine-textured materials, concave slopes, gentle slopes, and north-facing aspects. Slope shape and mineral soil texture are the geomorphic factors most closely associated with the ranking of soils along the morphological gradient from warm-dry-mineral to cold-wet-organic.